As I said, I think this is likely the best episode of the series. It's absolutely stunning.
We start where we left off after Ikumi has taken control of the Vital Guarder. It's excellent how nearly every character's reaction is chronicled to this development. All of the Zweis get screen time, with the most attention given to Juli and Stein. Kouji, Aoi, Reiko, Kozue, Yuki, Cullen, and Fina all get screen time as well as they look at how this new development changes their lives. This is an excellent example of how Ryvius is a true ensemble cast. While there are a few main characters, all of the secondary characters matter as well, and this scene really shows us that.
We are also shown the brutal new regime aboard the Ryvius, a stark difference from what we're used to seeing. The Ryvius looks peaceful at first, but then we see beyond the face of it and we see the truth. Everyone is living in fear. Juli displays this perfectly as she records it in her log. There was also more wonderful character development as Juli says that she wishes that she could shave off just one second from her time left on the Ryvius. This shows how desperate things have truly become, despite the calm outward appearance.
However, what makes this episode the best is the final scene, where Aoi is attacked. This showcases more excellent character development of both Kouji and Aoi, as Aoi copes with her attack and Kouji tries to console her in his own way. This is probably the most emotional moment in the show as both Kouji and Aoi are holding each other and sobbing. This is also a case where the dub works better than the sub. Alexandra Carter is excellent as the delirious and terrified Aoi while Brad Swaile is terrific as the broken Kouji. One of the most memorable moments of the show.
Overall, it's the characters that really matter in Infinite Ryvius. That's why space battles are used sparingly. It's not about the Vital Guarder or the coolest explosions. It's about Kouji. It's about Aoi. It's about Kozue, Ikumi, Juli, Lucson, Pat, Blue, Yuki, Cullen, Fina, Reiko, Stein, Gran, Charlie, Michelle, Criff, Nicks, Akihiro. It's about the people. And this episode showcases this like no other. That's why this is listed, for me, as the best episode of Infinite Ryvius.